PROJECT SUMMARY ? HUNTSMAN CANCER INSTITUTE, RODNEY STEWART Craniofacial Disorders (CD) account for approximately one-third of all birth defects in children and are a primary cause of infant mortality. A major barrier to improved CD diagnosis and treatment is an incomplete understanding of the genetic and biophysical mechanisms that shape different craniofacial elements during embryogenesis. The highly orchestrated collective cell movements of the cranial neural crest (NC) lay the foundation for construction of cartilage and bones in the head and face, and when impaired causes CD, including misplaced, reduced or missing craniofacial elements. The overall objective of the current project is to determine if biophysical forces are required to target collective cranial NC cell populations, also called NC streams, to precise locations in the head to drive craniofacial morphogenesis. Defining how craniofacial morphogenesis is orchestrated at the biophysical level is likely to reveal potential causes of human craniofacial disorders and identify new treatment strategies. The central hypothesis is that compression forces originating from the neural tube act on a sheet-like NC population to guide the second NC stream. Guided by published and preliminary data, this hypothesis will be tested by pursuing two specific aims: 1) generate a NC-specific tension sensor to measure forces within cranial NC streams and 2) determine if compression forces control migration of the second NC stream. The approach is innovative because it generates new tools to measure biophysical forces in vivo by taking advantage of the optical clarity and powerful imaging attributes of the zebrafish system using live embryos. The proposed research is significant because it is expected to advance and expand our understanding of how biophysical forces guide collective cell migration in many developmental and disease contexts, including craniofacial disorders, tissue regeneration and cancer invasion. In addition, the tools and data generated in this proposal will allow us to interrogate the genetic and cellular mechanisms controlling chemokine-dependent and biophysics-dependent targeting of cranial NC cells in a future R01- funded proposal, which is ultimately needed to reach our long-term goal of identifying treatments that can prevent or restore diseased craniofacial tissue.